1Universitätsklinikum Würzburg Medizinische Klinik und Poliklinik I Würzburg, Deutschland
Background
Left atrial enlargement (LAE) in aortic stenosis patients has been documented as an cardiovascular outcome determinant post transcatheter aortic valve implantation (TAVI). The impact of right-sided heart dimensions, particularly right atrial enlargement (RAE), on outcomes for TAVI patients remains less known. The present study aims to evaluate the prevalence of normal biatrial size (BA), isolated RAE, isolated LAE, and biatrial enlargement (BAE), and their respective prognostic implications in TAVI patients.
Methods
This retrospective study enrolled 859 patients under TAVI and with available comprehensive assessments of left atrial volume index (LAVi) and right atrial area (RAA) through transthoracic echocardiography. LAE was defined as LAVi >34 ml/m², and RAE as RAA >18 cm². Patients were categorized into four groups: "normal biatrial size (BA)" group (n=192), "isolated RAE" group (n=47), "isolated LAE" group (n=273), and "BAE" group (n=347). The primary endpoints, including all-cause death and cardiovascular (CV) death at 2 years post-TAVI, were compared among these groups.
Results
The prevalence of patients with normal BA, isolated RAE, isolated LAE, and BAE was 22.4%, 5.5%, 31.8%, and 40.4%, respectively. Over a 24-month follow-up period, all-cause mortality and cardiovascular (CV) mortality were highest in the BAE group, significantly surpassing the other three groups (CV mortality: 25.8% vs. 14.1% vs. 19.0% vs. 19.2%, Log Rank P=0.004; all-cause mortality: 20.6% vs. 10.7% vs. 12.0% vs. 11.6%, Log Rank P=0.001). All-cause or CV mortality was similar among patients with isolated LAE, isolated RAE, and normal BA size in this TAVI cohort. When compared to TAVI patients without BAE, the presence of BAE was significantly associated with an increased risk of all-cause mortality (23.9% vs. 16.0%, P=0.004) and CV mortality (19.0% vs. 10.5%, P<0.001).
Upon adjustment for potential covariates, including age, sex, EuroSCORE II, and atrial fibrillation, BAE remained significantly associated with an elevated risk of CV mortality, with a hazard ratio (HR) of 1.50 (95% CI 1.01-2.23, P=0.044). Atrial fibrillation (HR=1.80, 95% CI 1.31-2.47, P<0.001) and EuroSCORE II (HR=1.03, 95% CI 1.01-1.06, P=0.012) retained their status as independent factors associated with all-cause mortality risk, instead of BAE. Logistical regression revealed that patients with BAE exhibited a higher prevalence of atrial fibrillation and hyperuricemia, a lower prevalence of hyperlipidemia, larger left and right ventricles, and higher systolic pulmonary artery pressure.
Conclusions
Our study indicates that TAVI patients with biatrial enlargement face a significantly increased risk of cardiovascular mortality over a 24-month period, even after adjusting for various confounders. Future studies are warranted to explore if specialized monitoring strategy could improve the outcome of these patients.